1. Field of the Invention
The present invention relates to a lens barrel of a fixed-focus type of lens barrel.
2. Description of the Related Art
Hitherto, there are adopted various types of lens barrels in a camera and an electronic camera for instance, one of which is a fixed-focus type of lens barrel.
Recently, a thin type of camera or electronic camera is required. Adoption of a collapsible mount type of lens barrel may implement thinning of those cameras to some extent even for a fixed-focus type. However, further thinning of those cameras is required. In the body of those cameras, various members and mechanisms are disposed closely in such a manner that wasted spaces are almost eliminated. In order to implement more miniaturization of those cameras, it so happens that it is required that a shutter is disposed inside a lens barrel. In this case, simply, a size of the lens barrel in an optical axis is enlarged. And thus it is considered that even if a collapsible mount type of lens barrel is adopted, it is difficult to satisfy a requirement for thinning of those cameras in its entirety including the body.
In view of the foregoing, it is an object of the present invention to provide a fixed-focus type of lens barrel, and more particularly a lens barrel adapted to contributing to thinning a camera or electronic camera or the like adopting such a type of lens barrel.
To achieve the above-mentioned objects, the present invention provides a first lens barrel comprising: a main body frame; a first moving frame holding a first lens group and moving in an optical axis direction with respect to the main body frame; and a second moving frame holding a second lens group, which constitutes a fixed-focus lens in combination with the first lens group, and moving in the optical axis direction with respect to the main body frame, in which said first and second moving frames are moved by a single motor in the optical axis direction so as to provide collapse and extension with respect to said main body frame,
wherein in an extension state of said lens barrel, said first and second moving frames move in one united body in the optical axis direction while keeping a predetermined interval therebetween, and in a transitional process from the extension state to a collapse state, a mutual interval between said first and second moving frames is narrowed.
According to the lens barrel of the present invention as mentioned above, it is possible to reduce a length of the lens barrel in the optical axis direction at the time of a collapse, and thereby thinning a camera and an electronic camera adopting the lens barrel of the present invention.
To achieve the above-mentioned objects, the present invention provides a second lens barrel comprising: a main body frame; a first moving frame holding a first lens group and moving in an optical axis direction with respect to the main body frame; and a second moving frame holding a second lens group, which constitutes a fixed-focus lens in combination with the first lens group, and moving in the optical axis direction with respect to the main body frame, in which said first and second moving frames are moved by a single motor in the optical axis direction with respect to said main body frame, said lens barrel further comprising:
a guide shaft for guiding a movement of both said first and second moving frames in the optical axis direction, said guide shaft being fixed on said main body frame and being extended in the optical axis direction,
wherein said first moving frame has two first guide sections in which a movement in the optical axis direction is guided by said guide shaft, said two first guide sections being disposed at a predetermined interval therebetween in the optical axis direction, and said second moving frame has a second guide section in which a movement in the optical axis direction is guided by said guide shaft, said second guide section being disposed between said two first guide sections.
According to the second lens barrel of the present invention, the first moving frame has the two first guide sections, and the second guide section of the second moving frame is disposed between the two first guide sections. Consequently, when one of the moving frames is moved by a motor, another moving frame is also moved. That is, the first and second guide sections serve as not only a guide of a movement in the optical axis direction, but also a mechanism for performing coordinated movements of the two moving frames. Thus, such a simple mechanism makes it possible to implement coordinated movements of the two moving frames, and thereby contributing to a miniaturization of the lens barrel.
In the second lens barrel according to the present invention as mentioned above, it is preferable that between one of said two first guide sections and said second guide section, a spring member for enabling those guide sections are disposed. The use of the spring member makes it possible to surely maintain the two moving frames at predetermined relative positions in the use state.
Further, in the second lens barrel according to the present invention as mentioned above, it is preferable that said first and second moving frames are moved so as to provide collapse and extension with respect to said main body frame, and at the time of the extension, said first and second moving frames move in one united body in the optical axis direction while keeping a predetermined interval therebetween by an enabling force of said spring member, and at the time of the collapse, said first and second moving frames are maintained in a state that a mutual interval between said first and second moving frames is narrowed against the enabling force of said spring member.
This feature makes it possible to more reduce a length of the lens barrel in the optical axis direction at the time of a collapse, and thereby thinning a camera and an electronic camera adopting the lens barrel of the present invention.